Nonchromate metallic surface-treating agent, nonchromate metallic surface-treating method, and aluminum or aluminum alloy

ABSTRACT

An object of the present invention is to provide a nonchromate metallic surface-treating agent capable of achieving the corrosion resistance and adhesion with a coating film equal to a chromium phosphate surface-treating agent.  
     A nonchromate metallic surface-treating agent comprising  
     a water-soluble zirconium compound and/or a water-soluble titanium compound (1), an organic phosphonic acid compound (2) and a tannin (3),  
     wherein a content of zirconium and/or titanium of said water-soluble zirconium compound and/or the water-soluble titanium compound (1) is 40 to 1000 ppm on a mass basis,  
     a content of said organic phosphonic acid compound (2) is 20 to 500 ppm on a mass basis,  
     a content of said tannin (3) is 200 to 5000 ppm on a mass basis, and  
     a nonchromate metallic surface-treating agent has a pH of 1.6 to 4.0.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a nonchromate metallicsurface-treating agent, nonchromate metallic surface-treating method,and aluminum or an aluminum alloy.

[0002] As surface treatment of aluminum plates, a chromium phosphatesurface-treating agent has been used. Since chemical conversion coatsformed with the chromium phosphate surf-ace-treating agent are excellentin the corrosion resistance of the coatings alone and in the corrosionresistance and adhesion after applying various resin base coatings, theyare adopted in a wide range of uses of aluminum materials forconstruction materials, an electric home appliance, fin materials, carevaporators, beverage can materials and the like. However, in recentyears, there is required a nonchromate metallic surface-treating agent,which can provide the high corrosion resistance and adhesion equal to achromium phosphate surface-treating agent, from the view point ofenvironmental protection.

[0003] As a nonchromate chemical conversion treating agent, for example,a system where a zirconium or titanium compound is used in conjunctionwith a phosphoric acid compound for a beverage can material. However,since the chemical conversion coats formed by these systems are ofinferior corrosion resistance and adhesion after applying coating incomparison with the coatings formed by the chromium phosphatesurface-treating agent, these could not be used for a wide range ofuses.

[0004] Japanese Kokai Publication Sho-56-33468 discloses asurface-treating agent for aluminum comprising zirconium and/ortitanium, phosphate and fluoride. However, in this technology, it isinsufficient in the high adhesion with a coating and the corrosionresistance as a coating material.

[0005] Japanese Kokai Publication Sho-63-30218 discloses a nonchromatemetallic surface-treating agent comprising a water-soluble titaniumand/or zirconium compound, a tannin and/or a water-soluble orwater-dispersant high polymer. However, such a nonchromatesurface-treating agent is insufficient in the corrosion resistance as acoated material.

SUMMARY OF THE INVENTION

[0006] In consideration of the circumstances, an object of the presentinvention is to provide a nonchromate metallic surface-treating agentcapable of achieving the corrosion resistance and adhesion with acoating film equal to a chromium phosphate surface-treating agent.

[0007] This invention is a nonchromate metallic surface-treating agentcomprising

[0008] a water-soluble zirconium compound and/or a water-solubletitanium compound (1), an organic phosphonic acid compound (2) and atannin (3),

[0009] wherein a content of zirconium and/or titanium of saidwater-soluble zirconium compound and/or the water-soluble titaniumcompound (1) is 40 to 1000 ppm on a mass basis,

[0010] a content of said organic phosphonic acid compound (2) is 20 to500 ppm on a mass basis,

[0011] a content of said tannin (3) is 200 to 5000 ppm on a mass basis,and

[0012] a nonchromate metallic surface treating-agent has a pH of 1.6 to4.0.

[0013] Said organic phosphonic acid compound is preferably a compound inwhich phosphorus atom forming a phosphonic group combines with carbonatom.

[0014] This invention is a nonchromate metallic surface-treating methodcomprising

[0015] a step (A) of treating a substrate to be treated with saidnonchromate metallic surface-treating agent.

[0016] Said nonchromate metallic surface-treating method preferablycomprises an acid cleaning step followed by said step (A).

[0017] Preferably, an alkaline cleaning step is performed and then anacid cleaning step is performed before said step (A) is performed.

[0018] This invention is aluminum or an aluminum alloy having a coatobtained by said nonchromate metallic surface-treating method.

[0019] Said coat, after drying, preferably contains said water-solublezirconium compound and/or the water-soluble titanium compound (1) withzirconium and/or titanium atom of 4.0 to 30 mg/m², by mass per onesurface, and said-organic phosphonic acid compound (2) with phosphorusatom of 0.05 to 0.3 and said tannin (3) with carbon atom of 0.5 to 3relative to zirconium and/or titanium atom of said water-solublezirconium compound and/or said water-soluble titanium compound (1), on amass basis.

BRIEF DESCRIPTION OF THE DRAWING

[0020]FIG. 1 is a schematic view illustrating the shape of a sample forevaluating corrosion resistance.

EXPLANATION OF THE NUMERICAL SYMBOLS

[0021]1: Plane portion

[0022]2: Edge portion

[0023]3: Side portion

DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereafter, the present invention will be described in detail.

[0025] The nonchromate metallic surface-treating agent of the presentinvention is a surface-treating agent which can provide the excellentcorrosion resistance and adhesion with a coating film after applyingcoatings and which does not contain chromium. Particularly, it issuitably applicable to aluminum or an aluminum alloy, and can providethe excellent corrosion resistance and adhesion with a coating film, forexample, in applying it to aluminum or an aluminum alloy for beveragecans or an electric home appliance.

[0026] The nonchromate metallic surface-treating agent of the presentinvention contains a water-soluble zirconium compound and/or awater-soluble titanium compound (1). Though the water-soluble zirconiumcompound is not limited in particular so long as it is a compoundcontaining zirconium, a water-soluble zirconium compound containingfluorine is preferred since it has good stability in an applicable pHrange and it is high in the formability of a coat.

[0027] Said water-soluble zirconium compound containing fluorine is notlimited in particular, and examples thereof may include H₂ZrF₆,(NH₄)₂ZrF₆, K₂ZrF₆, Na₂ZrF6, Li₂ZrF6 and the like. These compounds maybe used alone or in combination of two kinds or more.

[0028] Though said water-soluble titanium compound is not limited inparticular so long as it is a compound containing titanium, awater-soluble titanium compound containing fluorine is preferred sinceit has the good stability in an applicable pH range and it is high inthe formability of a coat.

[0029] Said water-soluble titanium compound containing fluorine is notlimited in particular, and examples thereof may include H₂TiF₆,(NH₄)₂TiF₆, K₂TiF₆, Na₂TiF₆ and the like. These compounds may be usedalone or in combination of two kinds or more.

[0030] The content of the water-soluble zirconium compound and/or thewater-soluble titanium compound (1) with zirconium and/or titanium has alower limit of 40 ppm and an upper limit of 1000 ppm on amass basis inthe nonchromate metallic surface-treating agent. When the content isless than 40 ppm, there is a possibility that a sufficient amount ofzirconium or titanium in coats could be not obtained in a short-timetreatment and the adhesion and corrosion resistance could be degraded.When the content exceeds 1000 ppm, there is a possibility that theadhesion with a coating film after applying coatings could be degradedand also a possibility of being relatively expensive since theenhancement of performances and the reduction in treatment time are notrecognized. Preferably, the lower limit is 100 ppm and the upper limitis 300 ppm. It is noted that the content of the water-soluble zirconiumcompound and/or the water-soluble titanium compound is the sum of themasses of zirconium and titanium contained in the nonchromate metallicsurface-treating agent.

[0031] The nonchromate metallic surface-treating agent of the presentinvention contains an organic phosphonic acid compound (2).

[0032] Said organic phosphonic acid compound (2) means an organiccompound containing a phosphonic group (—PO₃H₂), and this compound (2)is preferably compound in which the phosphonic group (—PO₃H₂) combineswith carbon atom.

[0033] Among said organic phosphonic acid compounds (2), the compound inwhich the phosphonic group (—PO₃H₂) combines with carbon atom is notlimited in particular, and examples thereof may includeaminotri(methylenephosphonic acid) represented by the following formula(a), 1-hydroxyethylidene-1,1-diphosphonic acid represented by thefollowing formula (b), 2-phosphobutanone-1,2,4-tricarboxylic acidrepresented by the following formula (c), and the like.

[0034] Examples of the organic phosphonic acid compounds (2) may alsoinclude ethylenediaminetetra(methylenephosphonic acid) represented bythe following formula (d), diethylenetriaminepenta(methylenephosphonicacid) represented by the following formula (e), and the like.

[0035] Among the organic phosphonic acid compounds (2), aminotri(methylenephosphonic acid) represented by the formula (a),1-hydroxyethylidene-1,1-diphosphonic acid represented by the formula(b), and 2-phosphobutanone-1,2,4-tricarboxylic acid represented by theformula (c) are preferred since these are excellent in theprecipitability of coats and the corrosion resistance and adhesion witha coating film after applying coatings.

[0036] Preferably, the organic phosphonic acid compounds (2) arewater-soluble. When this is a water-soluble compound, the use of anorganic solvent is not required and a burden on the environment can bereduced.

[0037] The organic phosphonic acid compounds (2) maybe used alone or incombination of two kinds or more. It is noted that it is not preferredto include salts of organic phosphonic acid compounds, which is obtainedby replacing the hydrogen atom contained in a phosphonic group withalkaline metal, ammonium or the like, in the nonchromate metallicsurface-treating agent since the corrosion resistance of the formed coatis decreased.

[0038] The content of the organic-phosphonic acid compound (2) has alower limit of 20 ppm and an upper limit of 500 ppm on a mass basis inthe nonchromate metallic surface-treating agent. When the content isless than 20 ppm, there is a possibility that an appropriate amount ofphosphorus could be not obtained in the resulting coats to be formed andthe adhesion with a coating film after applying coatings could bedegraded. Even if the content exceeds 500 ppm, the organic phosphonicacid compound exists just only excessively and does not have an effectof enhancing the adhesion and corrosion resistance, and therefore thereis a possibility of being relatively expensive. Preferably, the lowerlimit is 50 ppm and the upper limit is 200 ppm.

[0039] The nonchromate metallic surface-treating agent of the presentinvention contains tannin (3). Said tannin (3) is also referred to astannic acid and is a generic name for aromatic compounds with acomplicated structure, which has a number of phenolic hydroxyl groupsbeing widely distributed over the plant kingdom. Said tannin (3) may behydrolyzable tannin or condensed tannin.

[0040] Examples of the tannin (3) may include hamameli tannin, Japanesepersimmon tannin, tea tannin, gallan tannin, gallnut tannin, myrobarantannin, divi-divi tannin, valonia tannin, catechin tannin and the like.In addition, the tannin (3) may also be decomposed tannins which areformed by decomposing tannins contained in plants by a method such ashydrolysis.

[0041] As the tannin (3), commercial products such as “Tannin AcidEssence A”, “B Tannic Acid”, “N Tannic Acid”, “Industrial Tannic Acid”,“Purified Tannic Acid”, “Hi Tannic Acid”, “F Tannic Acid”, “OfficinalTannic Acid” (all manufactured by Dainippon Pharmaceutical Co., Ltd.),“Tannin Acid: AL” (manufactured by Fuji Chemical Industry Co., Ltd.) canalso be used. The above-mentioned tannins may be used alone or incombination of two kinds or more.

[0042] Preferably, the tannin (3) has the number-average molecularweight of 200 or more. If decomposition of tannin proceeds too much andthe decomposed tannin becomes a compound with low molecular weight lessthan 200 when a product formed through the decomposition of tannin areused as the tannin (3), there is a possibility that the adhesion with acoating film after applying coatings could not be enhanced for lack ofproperties as tannin.

[0043] A content of the tannin (3) has a lower limit of 200 ppm and anupper limit of 5000 ppm on a mass basis in the nonchromate metallicsurface-treating agent. When the content is less than 200 ppm, there isa possibility that an appropriate amount of carbon could be not obtainedin coats to be formed and the corrosion resistance and adhesion with acoating film after applying coatings could be degraded. Even if thecontent exceeds 5000 ppm, there is a possibility of being relativelyexpensive since the enhancement of performances such as the corrosionresistance and adhesion with a coating and the reduction in treatmenttime are not recognized. Preferably, the lower limit is 500 ppm and theupper limit is 2000 ppm.

[0044] The nonchromate metallic surface-treating agent of the presentinvention has a pH within a range from a lower limit of 1.6 to an upperlimit of 4.0. When the pH is less than 1.6, the coat appearance becomesbad since the etching of the metal surface become excessive, and thecorrosion resistance of the obtained coat is degraded. When the pHexceeds 4.0, chemical conversion reaction does not proceedsatisfactorily and the chemical conversion coat is hard to be formed.The lower limit is preferably 1.8, more preferably 2.2. The upper limitis preferably 3.4, more preferably 2.8.

[0045] In the nonchromate metallic surface-treating agent of the presentinvention, an etching assistant agent, a chelating agent and a pHregulator can be further used as required in addition to theabove-mentioned components.

[0046] Examples of the etching assistant agent may include hydrofluoricacid, hydrofluoride, fluoboride and the like. Further, when as a sourceof fluorine ion, zirconium- or titanium complex which has been mentionedas the water-soluble zirconium compound or the water-soluble titaniumcompound (1) is used, it is preferred to use the fluorine compound inconjunction with this complex since the amount of produced fluorine ionis insufficient.

[0047] Examples of the chelating agents may include acids, which formcomplexes with aluminum, such as citric acid, tartaric acid and gluconicacid, and metal salts thereof.

[0048] Examples of the pH regulator may include acids or bases, which donot adversely affect surface treatments, such as nitric acid, perchloricacid, sulfuric acid, sodium nitrate, ammonium hydroxide, sodiumhydroxide and ammonia.

[0049] A nonchromate metallic surface-treating method of the presentinvention comprises a step (A) of treating a substrate to be treatedwith the nonchromate metallic surface-treating agent. By performing thestep (A), it is possible to provide the excellent corrosion resistanceand adhesion with a coating film after applying coatings to thesubstrate.

[0050] An example of the substrate to be treated includes metallic basematerials, and aluminum or an aluminum alloy is preferred. As thealuminum alloys, an aluminum alloy 5182 material, an aluminum alloy 5021material, an aluminum alloy 5022 material, an aluminum alloy 5052material, an aluminum alloy 3004 material, an aluminum alloy 3005material, an aluminum alloy 1050 material, an aluminum alloy 1100material and the like are suitably used. Applications of the substanceto be treated are not limited in particular, and examples thereofinclude an electric home appliance, cases for food and beverage,construction materials and the like.

[0051] In the step (A), a method of treating the substrate to be treatedis not limited in particular so long as it is a method of allowing thesubstrate to bring into contact with the nonchromate metallicsurface-treating agent, and examples of ordinary methods may include aspray method, a immersion method and the like. Among them, a spraymethod is preferably used.

[0052] Said step (A) is preferably performed at a temperature range froma lower limit of 30° C. to an upper limit of 80° C. When the temperatureis less than 30° C., a reaction rate is lowered and the precipitabilityof coats is degraded. Therefore, an extension of treatment time isrequired to obtain a sufficient amount of coats, and productivity isdecreased. When the temperature exceeds 80° C., there is a possibilitythat energy losses become large. More preferably, the lower limit is 50°C. and the upper limit is 70° C.

[0053] In the case where the step (A) is performed with a spray method,a treatment time preferably is within a range from a lower limit of 1second to an upper limit of 20 seconds. When the treatment time is lessthan 1 second, the amount of coats formed is insufficient and there is apossibility that the corrosion resistance and adhesion could bedegraded. When the treatment time exceeds 20 seconds, there is apossibility that etching proceeds excessively in formation of coatingsand the adhesion and corrosion resistance could be degraded. Morepreferably, the lower limit is 3 seconds and the upper limit is 8seconds.

[0054] After the step (A), water-washing treatment may be performed asrequired.

[0055] The water-washing treatment is performed once or more not toadversely affect on the appearances of coating film and the like. Inthis case, it is appropriate to perform the final water-washing withpure water. In this water-washing treatment, either spray or immersionmethod may be used, and the combination thereof may also be used.

[0056] The coats obtained through the step (A) are preferably driedafter water-washing. As a method of drying the coat, heat drying ispreferred, and an example thereof includes oven-drying and/or heatdrying through a forced circulation of hot air. These heat drying aregenerally performed at a temperature of 40 to 120° C. for 6 to 60seconds.

[0057] In the nonchromate metallic surface-treating method of thepresent invention, it is preferred that an acid cleaning step isperformed before the step (A) is performed. Furthermore, it is preferredthat an alkaline cleaning step is performed before the acid cleaningstep is performed. The most preferable aspect is a method comprising analkaline cleaning, a water-washing, an acid cleaning, a water-washing,nonchromate metallic surface treatment, water-washing and drying in thisorder.

[0058] The alkaline cleaning treatment is not limited in particular, andfor example alkaline cleaning which has been adopted in the alkalinecleaning of the metals such as aluminum and aluminum alloys can beperformed. In the alkaline cleaning treatment, generally, the alkalinecleaning is performed through the use of an alkaline cleaner. Further,the acid cleaning is performed through the use of an acid cleaner.

[0059] The alkaline cleaner is not limited in particular, and forexample an alkaline cleaner used in a usual alkaline cleaning can beadopted. An example of the alkaline cleaner includes “SURF CLEANER 360”manufactured by Nippon Paint Co., Ltd. The acid cleaner is not limitedin particular, and examples thereof include inorganic acids such assulfuric acid, nitric acid and hydrochloric acid, and “SURF CLEANERST160” manufactured by Nippon Paint Co., Ltd.

[0060] The acid cleaning and alkaline cleaning treatments are generallyperformed through a spray method. After the acid cleaning or alkalinecleaning treatment is performed, water-washing is performed to remove anacid cleaning agent or an alkaline cleaning agent remaining on thesurface of the basis material.

[0061] Preferably, the coat obtained by the nonchromate metallicsurface-treating method, after drying, contains the water-solublezirconium compound and/or the water-soluble titanium compound (1) withzirconium and/or titanium atom within a range having a lower limit of 4mg/m² and an upper limit of 30 mg/m² by mass per one surface. When thecontent thereof is less than 4 mg/m², there is a possibility that thecorrosion resistance after applying coatings could be degraded and whenthe content thereof exceeds 30 mg/m², there is a possibility that theadhesion with a coating after applying coatings could be degraded. Morepreferably, the lower limit is 10 mg/m² and the upper limit is 20 mg/m².It is noted that the term mass per one surface, after drying, of thewater-soluble zirconium compound and/or the water-soluble titaniumcompound means the sum of the masses of zirconium and titanium containedin the coat obtained by the nonchromate metallic surface-treatingmethod.

[0062] In the coat obtained by the nonchromate metallic surface-treatingmethod, the amounts of the respective component forming the coat can beobtained in desired amounts by appropriately setting the composition ofthe nonchromate metallic surface-treating agent, treatment temperatureand treatment time.

[0063] Preferably, the coat obtained by the nonchromate metallicsurface-treating method contains the organic phosphonic acid compound(2) with phosphorus atom within a range having a lower limit of 0.05 andan upper limit of 0.3 relative to zirconium and/or titanium atom of saidwater-soluble zirconium compound and/or said water-soluble titaniumcompound (1), on a mass basis. When this rate is less than 0.05, thereis a possibility that the adhesion with a coating film after applyingcoatings could be degraded and even if this rate exceeds 0.3, theorganic phosphonic acid compound exists just only excessively and doesnot have an effect of enhancing the adhesion, and therefore there is apossibility of being relatively expensive. More preferably, the lowerlimit is 0.1 and the upper limit is 0.15.

[0064] Preferably, the coat obtained by the nonchromate metallicsurface-treating method contains the tannin (3) with carbon atom withina range having a lower limit of 0.5 and an upper limit of 3 relative tozirconium and/or titanium atom-of said water-soluble zirconium compoundand/or said water-soluble titanium compound (1), on a mass basis. Whenthis rate is less than 0.5, there is a possibility that the adhesionwith a coating after applying coating could be degraded and when thisrate exceeds 3, there is a possibility that the corrosion resistanceafter applying coating could be degraded. More preferably, the lowerlimit is 1.0 and the upper limit is 1.5.

[0065] The respective amounts of zirconium and titanium of thewater-soluble zirconium compound and/or the water-soluble titaniumcompound (1) and the amount of phosphorus of the organic phosphonic acidcompound (2) in the coat obtained by the nonchromate metallicsurface-treating method can be measured by a X-ray fluorescencespectrometer, and the amount of the tannin (3) can be determined fromthe amount of organic carbon measured by a carbon/moisture content phaseanalyzer.

[0066] Aluminum or aluminum alloy according to the present invention isobtained by the nonchromate metallic surface-treating method. Since thusobtained aluminum or aluminum alloy is excellent in the corrosionresistance and adhesion with a coating film after applying coatings, itcan be suitably used for uses such as a case for beverages, an electrichome appliance and construction materials.

[0067] The nonchromate metallic surface-treating agent of the presentinvention comprises a water-soluble zirconium compound and/or awater-soluble titanium compound (1), an organic phosphonic acid compound(2) and a tannin (3), wherein a content of zirconium and/or titanium ofthe water-soluble zirconium compound and/or the water-soluble titaniumcompound (1) is 40 to 1000 ppm on a mass basis, a content of the organicphosphonic acid compound (2) is 20 to 500 ppm on a mass basis, a contentof the tannin (3) is 200 to 5000 ppm on a mass basis, and thenonchromate metallic surface-treating agent has a pH of 1.6 to 4.0. Thatis, since the nonchromate metallic surface-treating agent according tothe present invention contains not only the water-soluble zirconiumcompound and/or the water-soluble titanium compound (1) but also theorganic phosphonic acid compound (2) and the tannin (3), the corrosionresistance and adhesion with a coating film after applying coatings canbe enhanced by using said nonchromate metallic surface-treating agent.Thereby, it is possible to provide the excellent corrosion resistanceand adhesion with a coating film after applying coatings to metallicbase materials such as aluminum or an aluminum alloy by treating themetallic base materials with the nonchromate metallic surface-treatingagent and to suitably use the treated metallic base material forbeverage can materials, an electric home appliance, and constructionmaterials.

[0068] Since the nonchromate metallic surface-treating agent, thenonchromate metallic surface-treating method, and aluminum or analuminum alloy of the present invention comprise the constitutionsdescribed above, they can obtain the corrosion resistance and adhesionwith a coating film equal to a chromium phosphate surface-treatingagent. Thereby, they can be suitably adopted in a wide range of uses ofaluminum materials for construction materials, an electric homeappliance, fin materials, car evaporators, beverage can materials andthe like, particularly uses for an electric home appliance, constructionmaterials, and materials of beverage can cover.

EXAMPLES

[0069] Hereafter, although the present invention will be described morespecifically with reference to examples, the present invention is notlimited to these examples. Further, in the examples, term “part” means“mass part” unless otherwise specified.

[0070] (Preparation of Nonchromate Metallic Surface-Treating Agent)

Example 1

[0071] 9993 parts of ion-exchanged water was charged into the vesselequipped with an agitation apparatus. “Fluorozirconic acid” (2.3 parts:containing 17.6% of Zr) manufactured by Nippon Light Metal Co., Ltd. wasadded gradually thereto while agitating at room temperature. Whilefurther agitating, 0.7 part of “1-hydroxyethylidene-1,1-diphosphonicacid” manufactured by Morita Chemical Industries Co., Ltd. was addedgradually. Next, 4 parts of “Tannic Acid Essence A” (nonvolatile matter50%) manufactured by Dainippon Pharmaceutical Co., Ltd. was addedgradually while agitating. Subsequently, under agitation, hydrofluoricacid was compounded in such a manner that the concentration of freefluorine was 12 ppm to this treating agent and then ammonia was added toadjust pH of the treating agent to 2.6. The agitation was continued for10 minutes to obtain a slightly brown aqueous solution which containsfluorozirconic acid with zirconium of 40 ppm,1-hydroxyethylidene-1,1-diphosphonic acid with phosphorus of 20 ppm, andtannin of 200 ppm.

Examples 2 to 12, Comparative Examples 1 to 4

[0072] The nonchromate metallic surface-treating agents of Examples 2 to12 and Comparative Examples 1 to 4 were prepared in the same manner asExample 1 with the composition shown in Tables 1 and 2.

Example 13

[0073] Ion-exchanged water (9989.1 parts) was charged into the vesselequipped with an agitation apparatus. “Fluorotitanic acid” (1.5 parts:containing 29.3% of Ti) manufactured by Morita Chemical Industries Co.,Ltd. was added gradually while agitating at room temperature. Whilefurther agitating, 1.4 part of “1-hydroxyethylidene-1,1-diphosphonicacid” manufactured by Morita Chemical Industries Co., Ltd. was addedgradually. Next, 8 parts of “Tannic Acid Essence A” (nonvolatile matter50%) manufactured by Dainippon Pharmaceutical Co., Ltd. was addedgradually while agitating. Subsequently, under agitation, hydrofluoricacid was compounded in such a manner that the concentration of freefluorine was 12 ppm to this treating agent and then ammonia was added toadjust pH of the treating agent to 2.6. The agitation was continued for10 minutes to obtain a slightly brown aqueous solution which containsfluorotitanic acid with titanium of 45 ppm,1-hydroxyethylidene-1,1-diphosphonic acid with phosphorus of 40 ppm, andtannin of 400 ppm.

Examples 14 to 21, Comparative Examples 5 to 8

[0074] The nonchromate metallic surface-treating agents of Examples 14to 21 and Comparative Examples 5 to 8 were prepared in the same manneras Example 13 with the compositions shown in Tables 1 and 2.

Example 22

[0075] Ion-exchanged water (9987.9 parts) was charged into the vesselequipped with an agitation apparatus. Fluorozirconic acid (1.7 parts)and in succession 1.0 parts of fluorotitanic acid were added graduallyto the ion-exchanged water while agitating at room temperature. Whilefurther agitating, 1.4 parts of 1-hydroxyethylidene-1,1-diphosphonicacid was added gradually. Next, 8 parts of “Tannic Acid Essence A”(nonvolatile matter 50%) manufactured by Dainippon Pharmaceutical Co.,Ltd. was added gradually while agitating. Subsequently, under agitation,hydrofluoric acid was compounded in such a manner that the concentrationof free fluorine was 12 ppm to this treating agent and then ammonia wasadded to adjust pH of the treating agent to 2.6. The agitation wascontinued for 10 minutes to obtain a slightly brown aqueous solutionwhich contains fluorozirconic acid with zirconium of 30 ppm,fluorotitanic acid with titanium of 30 ppm,1-hydroxyethylidene-1,1-diphosphonic acid with phosphorus of 40 ppm, andtannin of 400 ppm.

Examples 23 to 25

[0076] The nonchromate metallic surface-treating agents of Examples 23to 25 were prepared in the same manner as Example 22 with thecompositions shown in Table 1.

Examples 26 to 28, Comparative Examples 9 and 10

[0077] The aqueous solution prepared in Example 4 (containingfluorozirconic acid with zirconium of 200 ppm,1-hydroxyethylidene-1,1-diphosphonic acid with phosphorus of 120 ppm,and tannin of 1400 ppm) was adjusted to pH of the range of 1.4 to 5using nitric acid or ammonia to obtain the nonchromate metallicsurface-treating agents of Examples 26 to 28 (Example 26: pH=1.6,Example 27: pH=3.0, Example 28: pH=4.0).

[0078] The nonchromate metallic surface-treating agents of ComparativeExamples 9 and 10 were obtained in the same manner (Comparative Example9: pH=1.4, Comparative Example 10: pH=5.0)

[0079] (Preparation of Chemical Conversion Treatment Plate)

[0080] Aluminum alloy 5182 plate materials were degreased (treated at65° C. for 3 seconds) using a 1% dilute solution of “Surf Cleaner 360”manufactured by Nippon Paint Co., Ltd., washed with water, and insuccession cleaned using a 1% dilute solution of sulfuric acid (treatedat 50° C. for 3 seconds) and then washed with water. The resultingaluminum materials were treated at 58° C. for 5 seconds with thenonchromate metallic surface-treating agent of the examples andcomparative examples using a spraying apparatus, and dried at a materialtemperature of 80° C. for 30 seconds to obtain surface treated metalplates.

Comparative Examples 11 to 13

[0081] Chemical conversion coats were formed under the same conditionsof cleaning and spray treatment as mentioned above except that “Alsurf4130” (Comparative Example 11: zirconium phosphate treating agent)manufactured by Nippon Paint Co., Ltd., “Alsurf 402” (ComparativeExample 12: zirconium treating agent (not containing phosphoric acidcompounds)) manufactured by Nippon Paint Co., Ltd., and “Alsurf 401/45”(Comparative Example 13: chromium phosphate treating agent) manufacturedby Nippon Paint Co., Ltd. Were used as treating agent.

[0082] (Measurement of Coat Mass)

[0083] Masses of zirconium, titanium, phosphorus and chromium of thedried coats obtained through examples and comparative examples weremeasured by using X-ray fluorescence spectrometer “XRF-1700”manufactured by Shimadzu Corp. With respect to masses of the tannin ofthe coats, the mass of carbon atoms derived from tannin were determinedby using a carbon/moisture content phase analyzer “RC 412” by LECO Corp.(USA). And, the masses of carbon atoms derived from tannin weredetermined with the following method.

[0084] Method of Determining Mass of Carbon Atom Derived from Tannin

[0085] (1) First, there was prepared a coat comprising only awater-soluble zirconium compound and/or a water-soluble titaniumcompound and an organic phosphonic acid compound. The masses of carbonand phosphorus derived from the organic phosphonic acid compound weremeasured and the mass ratio of carbon and phosphorus derived from theorganic phosphonic acid compound was determined to form a linearequation.

[0086] (2) Next, there was prepared a coat comprising a water-solublezirconium compound and/or a water-soluble titanium compound, an organicphosphonic acid compound and tannin. The masses of carbon and phosphorusof the coat were measured.

[0087] (3) From the linear equation obtained in the step (1), the massof carbon derived from the organic phosphonic acid compound wasdetermined based on the mass of phosphorus obtained in the step (2).

[0088] (4) From a difference between the mass of carbon obtained in thestep (2) (measured value) and the mass of phosphorus obtained in thestep (3) (calculated value), the mass of carbon derived from tannin wasdetermined.

[0089] The mass of zirconium in the zirconium compound, which wasobtained through the measurements, was represented as Zr, the mass oftitanium in the titanium compound was represented as Ti, the mass ofphosphorus derived from the organic phosphonic acid compound wasrepresented as P, and the mass of carbon atom derived from tannin wasrepresented as C, and the respective measurements were shown in Tables 1and 2. Further the ratios, that is, the sum of Zr and Ti vs. P and thesum of Zr and Ti vs. C, were shown in the tables. TABLE 1 Composition ofnonchromate metallic surface- treating agent (ppm) Organic phosphonicRatio Inorganic acid Tannic acid of respective components componentscomponents pH of metallic Coat coat masses (1) (2)* (3)**surface-treating mass (mg/m²) Zr.Ti Zr.Ti Zr Ti P1 P2 T1 T2 T3 agent ZrTi P C vs. P vs. P Examples 1  40 —  20 —  200 — — 2.6  4 — 0.3 31:0.075 1:0.75 2  40 —  40 —  400 — — 2.6  4 — 0.6 6 1:0.15  1:1.5  3200 —  30 —  300 — — 2.6 10 — 0.5 5 1:0.05  1:0.5  4 200 — 120 — 1400 —— 2.6 10 — 1.5 15 1:0.15  1:1.5  5 200 — — 180 1400 — — 2.6 10 — 1.5 151:0.15  1:1.5  6 200 — 120 — — 1400 — 2.6 10 — 1.5 15 1:0.15  1:1.5  7200 — 120 — — — 1400 2.6 10 — 1.5 15 1:0.15  1:1.5  8 200 — 270 — 4000 —— 2.6 10 — 3 30 1:0.3  1:3   9 500 — 100 — 1200 — — 2.6 20 — 1 101:0.05  1:0.5  10 550 — 290 — 3500 — — 2.6 20 — 3 30 1:0.15  1:1.5  11920 — 160 — 1600 — — 2.6 30 — 1.5 15 1:0.05  1:0.5  12 980 — 440 — 5000— — 2.6 30 — 4.5 45 1:0.15  1:1.5  13 —  45  40 —  400 — — 2.6 —  4 0.66 1:0.15  1:1.5  14 —  220  30 —  300 — — 2.6 — 10 0.6 6 1:0.15  1:0.5 15 —  220 120 — 1400 — — 2.6 — 10 1.5 15 1:0.15  1:1.5  16 —  220 — 1801400 — — 2.6 — 10 1.5 15 1:0.15  1:1.5  17 —  220 120 — — 1400 — 2.6 —10 1.5 15 1:0.15  1:1.5  18 —  220 120 — — — 1400 2.6 — 10 1.5 151:0.15  1:1.5  19 —  220 270 — 3000 — — 2.6 — 10 3 30 1:0.3  1:3   20 — 580 290 — 3000 — — 2.6 — 20 3 30 1:0.15  1:1.5  21 — 1000 440 — 5000 —— 2.6 — 30 4.5 45 1:0.15  1:1.5  22  30  30  40 —  400 — — 2.6  2  2 0.66 1:0.15  1:1.5  23 110  120 120 — 1400 — — 2.6  5  5 1.5 15 1:0.15 1:1.5  24 220  230 290 — 3000 — — 2.6 10 10 3 30 1:0.15  1:1.5  25 490 500 440 — 5000 — — 2.6 15 15 4.5 45 1:0.15  1:1.5  26 200 — 120 — 1400— — 1.6  4 — 0.6 8 1:0.15  1:2   27 200 — 120 — 1400 — — 3.0  7 — 0.9 121:0.13  1:1.7  28 200 — 120 — 1400 — — 4.0  4 — 0.6 10 1:0.15  1:2.5 

[0090] TABLE 2 Compositions of nonchromate metallic surface- treatingagent (ppm) Organic phosphonic Ratio Inorganic acid Tannic acid ofrespective components components components pH of metallic Coat coatmasses (1) (2)* (3)** surface-treating mass (mg/m²) Zr—Ti Zr—Ti Zr Ti P1P2 T1 T2 T3 agent Zr Ti P C vs. P vs. C Comparative 1  20 —  20 —  200 —— 2.6  2 — 0.3 3 10.15 1:1.5  examples 2  40 —  10 —  200 — — 2.6  4 —0.12 3 1:0.03 1:0.75 3  40 —  40 —  100 — — 2.6  4 — 0.6 1.2 1:0.151:0.3  4 1200 — 600 — 6500 ‘3 — 2.6 36 — 5.4 54 1:0.15 1:1.5  5 —  20 20 —  200 — — 2.6 —  2 0.3 3 1:0.15 1:1.5  6 —  45  10 —  200 — — 2.6 — 4 0.12 3 1:0.03 1:0.75 7 —  45  40 —  100 — — 2.6 —  4 0.6 1.2 1:0.151:0.3  8 — 1200 560 — 6000 — — 2.6 — 32 4.8 48 1:0.15 1:1.5  9  200 —120 — 1400 — — 1.4  2 — 0.2 6 1:0.1  1:3   10  200 — 120 — 1400 — — 5.0 1 — 0.1 6 1:0.1  1:6   11 ALSURF4130 10 — 4 0 1:0.4  — 12 ALSURF402 10— 0 0 — — 13 ALSURF401/45 Cr:20 10 0 1:0.5  —

[0091] Preparation of Coated Plate 1

[0092] Water-borne epoxy-based clear coating “Canliner 100” (nonvolatilematter 28%) manufactured by Nippon Paint Co., Ltd. was applied to theresulting chemical conversion treatment plates so as to form a coat of25 g/m² on a wet mass basis per one surface using a reverse roll coaterand this coat was baked at a material temperature of 260° C. for 30seconds using a conveyer type oven to obtain a coated aluminum materialhaving a coat with the mass of 7 g/m² after drying.

[0093] Preparation of Coated Plate 2

[0094] Solvent-borne polyester-based coating “Flekicoat #5000 White”(nonvolatile matter 50%) manufactured by Nippon Fine Coatings Inc., Ltd.was applied to the resulting chemical conversion treatment plates so asto form a coat of 15 g/m² on a wet mass basis per one surface using areverse roll coater and this coat was baked at a material temperature of230° C. for 60 seconds using a conveyer type oven to obtain a coatedaluminum material having a coat with the mass of 7.5 g/m² after drying.

[0095] (Evaluation Method)

[0096] The following evaluations were carried out and the results areshown in Tables 3 and 4.

[0097] 1. Stability of Nonchromate Metallic Surface-Treating Agent

[0098] The metallic surface-treating agents prepared in the manners werestored at 40° C. for 30 days, and the appearances of the treating agentswere visually tested. In Tables 3 and 4, to the samples which did notexhibit abnormal conditions such as occurrences of a whitish portion,precipitations and coagulating substances and had better appearances,there were put an expression by“∘”, and to the samples which causedabnormal conditions, there were put descriptions of the content ofabnormal conditions.

[0099] 2. Coat appearance

[0100] The surfaces of the chemical conversion treatment plates obtainedin the manners were visually tested. In Tables 3 and 4, to the sampleswhich did not exhibit abnormal conditions such as occurrences ofcissing, unevenness and significant tarnish and had better appearances,there were put an expression by “∘”, and to the samples which causedabnormal conditions, there were put descriptions of the content ofabnormal conditions.

[0101] 3. Adhesion Strength

[0102] Respective coated surfaces of the two same coated plates weremutually bonded by using a hot-melt polyamide film “Diamide Film #7000”manufactured by Daicel Chemical Industries, Co., Ltd. Bonding wasperformed by fixing two plates to each other by applying pressure at200° C. and at a pressure of 7 kg/cm² for 1 minute with a hot presstester. The resulting bonded plate was cut out in width of 5 mm, andpeeled off at a speed of 200 mm/min with a tensilon tester and a forceapplied then was measured (unit: kgf/5 mm) (Polyester-based coatingscannot be bonded in such a bonding-way and therefore cannot be tested.).

[0103] It was taken as an accepted level to exhibit the value which wasequal to or higher than that of the coated plate treated with a chromiumphosphate treating agent.

[0104] 4. Adhesion After Water Resistance Test

[0105] The coated aluminum plates were immersed for 60 minutes in boiledwater of 100° C. Immediately after the coated aluminum plates wereremoved out of the boiled water, 100 of cross-hatch were provided withdistances of 1 mm, and tape-peeling test were performed with cellophanetapes and the number of peeling were counted. It was taken as anaccepted level that there were no peeling portions.

[0106] 5. Corrosion Resistance

[0107] The coated aluminum plates were processed to the cups having theconfiguration illustrated in FIG. 1 so that the coated surface of thealuminum plates became convex. The resulting cups were immerged in themixed aqueous solution of 2% citric acid solution and 2% salt water,being kept at 50° C., for 72 hours, and after taking it out, states ofcorrosion of the respective portions, that is, a plane portion 1, anedge portion 2 and a side portion 3, which are shown in FIG. 1, wererated on a scale of 5 points according the following criteria and theaverage points of the respective portions were determined.

[0108] 5 points: there was no corrosion.

[0109] 4 points: there was little corrosion (side portion: corrosionportions of 0.5 mm in diameter were 10 points or less, edge portion:corrosion portions of 0.5 mm in diameter were 5 points or less).

[0110] 3 points: there was corrosion (side portion: corrosion portionsof 1 mm in diameter were 20 points or less, edge portion: corrosionportions of 1 mm in diameter were 10 points or less)

[0111] 2 points: there was corrosion (side portion: corrosion portionsof 3 mm in diameter were-20 points or less, edge portion: corrosionportions of 3 mm in diameter were 10 points or less).

[0112] 1 point: there was corrosion wholly (more than halves of the sideportion, and the edge portion were corroded).

[0113] It was taken as an accepted level that an average of the ratingpoints exhibits the value which was equal to or higher than that of thecoated aluminum plate treated with a chromium phosphate treating agent.TABLE 3 Evaluation of coating material Solvent-borne Water-borneepoxy-based coating polyester-based coating Adhesion Adhesion Stabilityof Adhesion after Adhesion after surface-treating Coat Adhesion waterresistance Corrosion water resistance Corrosion agent appearancestrength test resistance test resistance Examples 1 ◯ ◯ 1.3 100/100 3.3100/100 4.3 2 ◯ ◯ 1.6 100/100 3.3 100/100 4.3 3 ◯ ◯ 1.9 100/100 4.0100/100 4.7 4 ◯ ◯ 2.0 100/100 4.3 100/100 5.0 5 ◯ ◯ 2.1 100/100 4.3100/100 4.7 6 ◯ ◯ 2.2 100/100 4.3 100/100 4.7 7 ◯ ◯ 2.1 100/100 4.3100/100 5.0 8 ◯ ◯ 2.1 100/100 4.3 100/100 4.7 9 ◯ ◯ 1.7 100/100 4.3100/100 4.7 10 ◯ ◯ 1.9 100/100 4.0 100/100 4.7 11 ◯ ◯ 1.3 100/100 4.3100/100 4.7 12 ◯ ◯ 1.2 100/100 4.0 100/100 4.3 13 ◯ ◯ 1.6 100/100 3.3100/100 4.3 14 ◯ ◯ 1.4 100/100 4.0 100/100 4.7 15 ◯ ◯ 1.8 100/100 4.0100/100 4.7 16 ◯ ◯ 2.2 100/100 4.0 100/100 4.7 17 ◯ ◯ 2.2 100/100 4.0100/100 4.7 18 ◯ ◯ 2.3 100/100 4.0 100/100 4.7 19 ◯ ◯ 2.0 100/100 4.0100/100 4.7 20 ◯ ◯ 1.6 100/100 4.0 100/100 4.3 21 ◯ ◯ 1.2 100/100 4.0100/100 4.3 22 ◯ ◯ 1.4 100/100 3.3 100/100 4.3 23 ◯ ◯ 2.3 100/100 4.0100/100 4.3 23 ◯ ◯ 2.3 100/100 4.0 100/100 4.7 24 ◯ ◯ 1.6 100/100 4.0100/100 4.3 25 ◯ ◯ 1.2 100/100 4.0 100/100 4.3 26 ◯ ◯ 1.4 100/100 3.3100/100 4.3 27 ◯ ◯ 1.9 100/100 4.0 100/100 4.7 28 ◯ ◯ 1.3 100/100 3.3100/100 4.3

[0114] TABLE 4 Evaluation of coating material Solvent-borne Water-borneepoxy-based coating polyester-based coating Stability of AdhesionAdhesion surface- Adhesion after Adhesion after treating Coat Adhesionwater resistance Corrosion water resistance Corrosion agent appearancestrength test resistance test resistance Comparative 1 ◯ ◯ 1.1 100/1003.0  88/100 3.7 examples 2 ◯ ◯ 1.2 100/100 3.3  90/100 4.0 3 ◯ ◯ 1.1100/100 3.3  93/100 4.0 4 ◯ ◯ 0.9 100/100 3.7  90/100 4.3 5 ◯ ◯ 1.3100/100 2.7  81/100 3.3 6 ◯ ◯ 1.3 100/100 3.3  83/100 4.3 7 ◯ ◯ 1.4100/100 3.0  86/100 4.0 8 ◯ ◯ 1.2 100/100 3.3  92/100 4.3 9 ◯ Whitening1.0 100/100 2.7  51/100 3.7 10 Whitish liquid Nib 0.8 100/100 2.3 33/100 3.0 11 ◯ ◯ 1.6 100/100 3.0  89/100 3.7 12 ◯ ◯ 1.3 100/100 3.7 11/100 4.0 13 ◯ ◯ 1.0 100/100 3.3 100/100 4.3

[0115] The nonchromate metallic surface-treating agents obtained throughexamples were high in the stability of liquid and the coats obtainedwith the treating agents were excellent in the adhesion and corrosionresistance. The coats obtained with the treating agents of ComparativeExamples 1 to 8, in which the amounts of water-soluble zirconiumcompound and/or water-soluble titanium compound (1), organic phosphonicacid compound (2) and tannin (3) were out of the ranges of the presentinvention, were poor in the adhesion and corrosion resistance. Further,Comparative Examples 9 and 10, in which pHs ranged out of the ranges ofthe present invention, were not only low in the adhesion and corrosionresistance but also poor in the stability of treating agents, and theobtained coats whitened. Furthermore, the coating films obtained withthe nonchromate metallic surface-treating agent of the examplesexhibited the adhesion and corrosion resistance which is equal to orhigher than that obtained with the treating agents of ComparativeExamples 11 to 13.

1. A nonchromate metallic surface-treating agent comprising awater-soluble zirconium compound and/or a water-soluble titaniumcompound (1), an organic phosphonic acid compound (2) and a tannin (3),wherein a content of zirconium and/or titanium of said water-solublezirconium compound and/or the water-soluble titanium compound (1) is 40to 1000 ppm on a mass basis, a content of said organic phosphonic acidcompound (2) is 20 to 500 ppm on a mass basis, a content of said tannin(3) is 200 to 5000 ppm on a mass basis, and a nonchromate metallicsurface treating-agent has a pH of 1.6 to 4.0.
 2. The nonchromatemetallic surface-treating agent according to claim 1, wherein saidorganic phosphonic acid compound is a compound in which phosphorus atomforming a phosphonic group combines with carbon atom.
 3. A nonchromatemetallic surface-treating method comprising a step (A) of treating asubstrate to be treated with the nonchromate metallic surface-treatingagent according to claim 1 or
 2. 4. The nonchromate metallicsurface-treating method according to claim 3 comprising an acid cleaningstep followed by said step (A).
 5. The nonchromate metallicsurface-treating method according to claim 3, wherein an alkalinecleaning step is performed and then an acid cleaning step is performedbefore said step (A) is performed.
 6. Aluminum or an aluminum alloyhaving a coat obtained by the nonchromate metallic surface-treatingmethod according to any of claims 3 to
 5. 7. The aluminum or aluminumalloy according to claim 6, wherein said coat, after drying, containssaid water-soluble zirconium compound and/or the water-soluble titaniumcompound (1) with zirconium and/or titanium atom of 4.0 to 30 mg/m², bymass per one surface, and said organic phosphonic acid compound (2) withphosphorus atom of 0.05 to 0.3 and said tannin (3) with carbon atom of0.5 to 3 relative to zirconium and/or titanium atom of saidwater-soluble zirconium compound and/or said water-soluble titaniumcompound (1), on a mass basis.